DNSsy is described as 'Provides a comprehensive test and report on the health of your DNS'. There are four alternatives to DNSsy, not only websites but also apps for . The best alternative is intoDNS, which is free. Other great sites and apps similar to DNSsy are W3dt.net (Free), Dnsstuff (Freemium) and SolveDNS (Free).
W3dt.net offers DNS & Network Troubleshooting tools which are dedicated to providing relevant real-time data regarding networks, websites and other technical resources, free of charge for more than a decade!.
Free DNS Report - Tests A, MX, SOA, SPF records for speed, accuracy, and consistency. Includes timed out information which reports how many times a name server timed out. Also reports the average speed of your name server.